If someone is up to something, I have to act as normally as possible, she said to herself as she waited.

She was about to push towards the door when something caught her attention: a microscopic movement just at the limits of her senses. And then the sound, to her left and right: the gentle hiss of air passing through dozens of tiny motors. She jerked her head to and fro frantically, trying to sense one of the nanostations in the faint light.

Weeks spent avoiding the lone nanostation in the Lounge had taught Su Ning a great deal about detecting them; the sound they made, the small flurry of air as they moved through the modules, the occasional glint as the light would catch one at just the right angle.

It was Nightmode in Su Ning’s quarters, and she was terrified.

Instead of the lone nanostation that would patrol the air at night, making sure everything was safe, she knew she was surrounded by tens of them, shooting past her head as fast as they could go. They had appeared suddenly, as if they had been waiting for her to move.

She turned her eyes to the door connecting her quarters to the Hygiene Bay and tensed.  Between her and the door, there was a small flash of light, like a spark shooting from a fire.

Pushing on her arms with all her might, she shot for the opening, ten feet away.

The nanostations were executing their carefully programmed drill, a simple systems test, for safety reasons.

The monitor station sat in the centre of the room, motionless, waiting.

The other stations calculated their vectors with infinite precision, converging with great speed on a point next to the monitor. They came together within a millisecond of each other.

The monitor station, millimetres away, detected the small explosion in its vicinity: a sphere of heat exceeding two hundred degrees Celsius. A fire. No time to evacuate in the oxygen-rich atmosphere.

The door to the Hygiene Bay was sealed in the instant before Su Ning reached it.

Captain Yves Montreaux shot upright in his bed and looked for the lights. A deafening alarm was ringing through the Clarke, but its tone told him that his quarters were not in the danger zone.  He lunged toward the door.

Poking his head through the short tunnel and into the Hygiene Bay, he saw the faces of Dr Richardson and Captain Marchenko coming out of the modules to his left and right, both with similarly confused expressions.  Around all three of their doors were the safe, blue lights indicating the problem was elsewhere.

“Su Ning!” he cried as he pulled out of the tunnel, groping for handholds on the shiny metallic walls of the Hygiene Bay as he struggled to reach her quarters.

The light around her sealed door was flashing red.

A small square control box recessed into the side of the door was also flashing red: Module Evac.

Montreaux knew what it meant. They didn’t have much time.

“Richardson, get over here!” he barked as he ripped the cover off the control panel. “Open this door!”

The scientist reached his side and saw the warning message. Her jaw dropped. “I can’t,” she managed to say. “It’s flushing the module, all of the air is being sucked into space! Even if I could, opening the door could kill us all!” She looked and sounded helpless.

“Do it!” he screamed. He started banging on the sealed door with his fist and shouting through the metal. Hearing no response he redoubled his efforts with a double fisted blow that sent him cart-wheeling backwards.  His arms and legs flailed around as he tried to stop himself from spinning, and he finally managed to bring himself back to the door. He had raised his fist for another blow when a firm hand caught his wrist and stopped him.

“Captain, it is too late.” Marchenko said, his accent coming through stronger than usual in his voice. “If she was in there, she is gone.”

Montreaux turned round in a daze and pushed towards the Lounge. “She may be in here!” he said. “She used to come in here at night!” He looked through into the large spherical room and scanned round it several times before giving up, his body going limp in the connecting tunnel.

He felt a gentle tug at his legs as he was pulled back into the Hygiene Bay. He came to a halt facing Dr Richardson. In the background, the noise of the alarm had stopped.

“Yves,” she started.

Behind her, he saw that Marchenko was sliding into Su Ning’s quarters: the door was now lit in blue and had opened. Montreaux pushed past Richardson and reached the module, his eyes full of hope.

His face fell when he saw the Russian, cradling Su Ning’s limp body.

Chapter 22

Mars filled the window of the Lounge as the Clarke completed another orbit. Captain Montreaux looked out over the reddish brown swirl of the Martian atmosphere and sighed.

He could still remember his last private exchange of words with Su Ning, at that very window, overlooking the stars. It was hard to believe that six weeks had passed since the accident.

The official word from Mission Control had been that a group of malfunctioning nanostations had collided inside the Chinese officer’s quarters, causing a small fireball that had initiated the isolation procedure.  On its own, this would not have been fatal, but a secondary fault in the Clarke’s safety protocols had caused it to issue a command to flush the module and put out the fire, despite the fact that no fire could be detected. All the computer had to do to avoid the situation was check the nanostation for a second reading, thereby gaining a measure by which to assess the risk to the spaceship; had it done so, it would have established that the fire had already stopped, and the area was safe.

The faulty programming caused all of the air to be evacuated from the module. The sudden, unexpected drop in atmospheric pressure and temperature killed Su Ning in less than two minutes.

Her body had been stored inside the Clarke in an empty refrigeration unit that had once contained food supplies for the outbound journey. The remaining crew members had pasted a photo of the astronaut on the door of the unit, along with a few personal messages.  The mourning process had been especially difficult in the depths of space; the melancholic isolation of the had prolonged their silent suffering for well over a week.

In the end, Mission Control had started to play music through the internal communication system on board the Clarke.  Within two days, the crew had begun socialising and even laughing again. It was amazing the effect music could have on people.

But Montreaux knew that for his part it was all a charade. While Dr Richardson and Captain Marchenko had eventually been satisfied by the explanation of the incident, the commanding officer had seen no accident in Su Ning’s death.

Instead, he saw a very clear warning.

They had been orbiting the planet for a week now, waiting for a storm on the surface to let up.  It was important that the Clarke’s landing module, the MLP, entered the atmosphere in quiet weather if possible, for two reasons.

Firstly, the safety of the crew was of major concern. The MLP was the largest landing craft ever to enter an alien atmosphere, and also the heaviest.  Designers had initially toyed with the idea of a winged craft, similar to the old fashioned NASA Space Shuttle. But the lack of sufficiently flat surfaces to land on added to the thin atmosphere made it a far too risky option.  A traditional parachute driven approach was therefore quickly adopted.  Six chutes would deploy to bring the craft down safely, aided by inflatable cushions on the underside of the MLP.  It was therefore vitally important that they did not land in the middle of a storm, as the high winds could easily disrupt the flow of air through the parachutes, and cause the craft to list uncontrollably during its descent. A landing under such conditions could be fatal, and an unfortunate premature ending to the already blighted Mars mission.